Semi-trailer tractor trucks also known as a semi, or tractor-trailer, will frequently be configured to tow a second semi-trailer behind the first in a configuration known as a “double trailer”. In such a configuration it is necessary that the tail lamps, running lamps, brake lights, and signal lights of the towed trailer be connected into the tractor so proper illumination and turn and brake signals are operating on the rear-most trailer. This is typically accomplished by providing a wiring harness that travels the length of the first trailer to communicate electrical signals generated by the tractor to the rear-most trailer. The wiring harness allows the rear-most trailer to be connected into the electrical system of the tractor thereby receiving the electrical impulses that cause illumination of the tail lamps, running lamps, brake lights, and signal lights of the towed trailer. The wiring harness must be affixed to the trailer and at the front and/or rear of the trailer. The end terminal or socket of the wiring harness must be installed into a portion of the frame of the trailer. Generally, such installation comprises the placement of the receptacle or socket (typically known as an SAE standard J560 connector) within a round hole or void that has been made in a front or rear metal frame piece of the trailer. It will be appreciated that a first end of the wiring harness has an electrical connector located in an opening on the forward facing surface of the trailer, (or workpiece) and is commonly referred to as the “Nose Plug.” A second electrical connector is located in an opening on the rearward facing surface of the trailer and may be referred to as the “Tail Plug.” Both plugs or receptacle or sockets are defined in SAE specification J560. The connector at the rear of the trailer is suitable for connecting another tandem trailer and serves as the power output connector to the trailer in-tow or dolly in-tow.
The challenge in trailer wiring is ensuring a waterproof seal at the trailer's power connector. The electrical connector is exposed to all forms of weather and highway driving speeds and vibrations. This environment and these conditions make it essential that any connector be sealed against the elements and that the integrity of such sealing against the elements be maintained during installation to avoid corrosion of the connector and wiring harness. Generally, this requirement for excluding moisture and dirt has resulted in wiring harnesses that are fully formed with integral receptacles or socket and with molded plastic covers that extend the length of the wiring harness and the receptacles. Therefore, installation of a wiring harness requires either insertion of one end of the harness through a mounting hole in the trailer frame and pulling the 30 to 60 feet of wire through the hole or having a connector that can be mounted in the hole from the back-side of the hole. The first of these installation methods can result in the scraping and cutting of the wiring harness on the edges of the metal in which the hole or void is made.
Therefore, it would be beneficial to have a receptacle or socket that allows for rear installation of the socket onto the trailer frame to avoid pulling the whole of the wiring harness through the hole in the trailer frame. It would be a further benefit if the socket is integrally sealed against moisture with the wires or electrical leads that are attached to the connector. It would be a further benefit if the means for attaching the connector avoids the creation of entry points for moisture of areas that will retain moisture and lead to corrosion of the electrical components and connections of the socket or connector.